Everywhere Republican presidential candidate Mitt Romney goes, he is followed by “trackers” with video cameras, hoping to catch him making an embarrassing gaffe.

The effort, run by a super political action committee, is funded in part by wealthy Californians. American Bridge 21st Century pulled in more than $1 million from California donors last year, more than from any other state, according to campaign filings.

American Bridge is a liberal research organization in hot pursuit of what is now known as a “macaca” moment. In 2006, then-Sen. George Allen, R-Va., used the term to refer to an Indian American volunteer tracker for Allen’s opponent, contributing to the failure of his re-election campaign.

American Bridge’s team of about 16 video trackers follows Romney and his Republican rivals to all their events and will become increasingly active in Senate and House races this year, said spokesman Chris Harris. About 25 researchers comb public statements, business records and campaign contributions, and a communications team works to get the message out “in the political bloodstream,” Harris said.

The state’s biggest donor to American Bridge, with a $200,000 contribution, was Anne Earhart, an Orange County environmentalist, philanthropist and heiress to the Getty Oil fortune. Earhart is founder of the Marisla Foundation, which funds environmental causes and gave $15,000 to the Center for Investigative Reporting for environmental reporting in 2006.

Hollywood producer and Democratic megadonor Steve Bing – known for, among other things, a paternity dispute with actress Elizabeth Hurley – gave $150,000.

Several other big donations came from the San Francisco Bay Area. Susie Buell, co-founder of Esprit clothing company and longtime friend of Secretary of State Hillary Clinton, gave $100,000.

American Bridge is “dedicated to making facts matter” by holding Republicans accountable for what they say, desJardins wrote in an e-mail. He wants American Bridge to catch Romney, for example, appealing to primary voters with more conservative rhetoric than what he would say in the general election.

“I don’t care if he takes one position or another, but I don’t think he should have his cake and eat it too – if he wants to tell one group what he stands for, then everyone else should hear the same thing,” desJardins wrote.

Paul Zygielbaum, an anti-asbestos advocate and chief operating officer of a glucose monitoring device company, also gave $100,000. Stephen Silberstein, co-founder of a library technology company and former board member of the Sierra Club Foundation, chipped in $100,000 as well.

Several of American Bridge’s donors are affiliated with the Democracy Alliance, a network of top-level liberal donors that strategically coordinates giving. The group’s chairman, Taco Bell heir Rob McKay, gave $50,000 to American Bridge.

American Bridge works with other super PACs, like the pro-Obama Priorities USA Action, to provide research and video clips that can then be used in attack ads.

“They can spend their resources and their time doing what they do best, and we can focus on what we do best,” Harris said.

In October, American Bridge accused Sen. Scott Brown, R-Mass., of plagiarism after it discovered a personal message on Brown’s website matched a speech by former Sen. Elizabeth Dole. Brown’s office blamed a staff oversight.

When Romney called his income from speaking fees “not very much,” American Bridge raced out with an online video criticizing the comment.

The super PAC also provided research for a Los Angeles Times story on tax breaks for a steel company that Romney invested in when he was with Bain Capital.

The group was formed in 2010 by conservative-turned-liberal operative David Brock, who also founded Media Matters for America.

“After we got our butts kicked in the midterms, David Brock realized something needed to be done,” Harris said.

The result is “the next iteration of technology impacting politics,” said Barbara O’Connor, professor emeritus and former director of the Institute for the Study of Politics and Media at CSU Sacramento.

“It’s the marrying of the irate grassroots folks who used to dog people and try to get them to say something they’d regret later … combined with large amounts of money and staff,” she said.

But O’Connor said the incessant focus on gaffes has a big downside.

“What it produces is candidates that are a lot more careful, don’t say anything and are vanilla, because they don’t want to be caught in that trap,” O’Connor said. “And that makes voters even more unhappy.”